The present invention relates to sunshades for use on building exteriors. More particularly, the invention relates to a sunshade for protecting windows from direct exposure to the sun. In a preferred embodiment, the sunshade also includes photovoltaic cells for generating electricity.
There is an increased awareness of the need for sustainable design in today""s architecture. Accordingly, architects are increasingly specifying building products having a reduced impact on the environment. Exterior shading devices such as sunshades meet this need.
Many architects and building designers choose sunshades to differentiate their wall elevations aesthetically. Architects also choose to incorporate sunshades in order to reduce solar heat gain. For some applications sunshades are a more desirable method of reducing glare than reflective glass because sunshades allow a high degree of natural lighting that is not possible with reflective coatings.
Sunshade systems have heretofore mostly been custom made. Accordingly, they are expensive design options. A pre-engineered sunshade system having design flexibility engineered into the product provides a balanced approach to cost and aesthetics. Additionally, a pre-engineered sunshade system that is packaged as part of a curtain wall system gives the architect and building owner the confidence of single source responsibility. These desirable benefits to architects and owners are not currently available in custom manufactured sunshade systems.
The need for sustainable design in building construction can also be satisfied by incorporating photovoltaic (PV) modules into the building structure. Accordingly, there is a need for sunshade systems having integrated PV modules. This configuration can satisfy the architect""s desire for a truly sustainable design element.
A principal objective of the present invention is to provide a sunshade system for buildings having sufficient design flexibility that it can be utilized at a variety of different locations and can be modified to have different appearances.
A related objective of the present invention is to provide a sunshade system having pre-engineered components so that it is manufactured and installed more economically than custom sunshade systems.
A further objective of the invention is to provide a pre-engineered sunshade system including photovoltaic cells for generating electricity.
Additional objectives and advantages of the invention will become apparent from the following detailed description of a preferred embodiment.
In accordance the present invention there is provided a sunshade for attachment to an exterior of a building. The sunshade is preferably attached to window mullions so as to protect a window from direct exposure to the sun.
The sunshade includes at least one connecting bracket for attachment to a window mullion, at least one blade support strut attached to the connecting bracket at a first joint, and a plurality of louvered blades supported by the blade support strut. Optionally, the sunshade may also include one or more photovoltaic cells supported by the blades and an electric cable for connecting each photovoltaic cell to an electric circuit.
The sunshade is suited for attachment to two laterally spaced, generally vertically extending window mullions in a curtain wall of a building. The mullions are components of a window frame. The mullions are preferably aluminum alloy extrusions strengthened by steel reinforcements or reinforcing bars.
The sunshade includes at least one connecting bracket suited for attachment to a mullion. A curtain wall system with two mullions has a connecting bracket extending from each mullion. The connecting brackets are made from aluminum alloy plate shaped to a desired configuration.
The connecting brackets are each joined to a blade support strut at a first joint. Each blade support strut is preferably an aluminum alloy plate cut to include a plurality of struts or blade support arms extending away from the first joint. A pivot angle between the connecting bracket and the blade support at the first joint is preselected in accordance with the degree of shading desired at a location where the sunshade is installed. For example, architects and building owners generally need greater sunshade extension in northern latitudes to attain the same degree of shading as in southern latitudes.
The louvered blades are preferably made from a plurality of interconnected aluminum alloy extrusions. At least one of the extrusions has opposed end portions supported by a pair of laterally spaced blade support struts at a second joint. The louvered blades are positioned on the second joint to a fixed profile angle that is preselected to optimize shading at the latitude where the sunshade is situated.
In a preferred embodiment, the louvered blades each include a top wall defining a recess holding a photovoltaic cell. A sunshade having three louvered blades each supporting a 20-watt photovoltaic cell is capable of generating 60 watts at peak daylight hours when electricity consumption is highest. The sunshade includes electric cables connecting the photovoltaic cells to an electric circuit inside the building.